The public perception of the green belt differs greatly from the reality. Photograph: Graham Morley / Alamy/Alamy

1. It's not all green and pleasant landContrary to myth, the only function of the green belt is to stop urban sprawl (cities growing into one another). Green belt land has no inherent ecological or agricultural value, nor is it chosen because it has natural beauty or protected wildlife. Much of it is poor-quality scrubland or used for intensive farming, and defined as green belt purely to stop cities from growing. Most is privately owned and not accessible to the public.

2. It doesn't actually stop cities growing The green belt has not stopped growth; it has just pushed it further out into rural areas not defined as green belt. Towns and cities grow by developing beyond their green belts and creating what we have come to term a commuter belt. The London commuter belt now arguably stretches from the Isle of Wight to Yorkshire.

In south Cambridgeshire, 19,000 new homes are to be built but all of them beyond the rigid green belt that surrounds the city of Cambridge. Many residents of new houses built beyond green belts will end up commuting further to work, creating more traffic and emitting more pollution. The pressure to develop homes within city boundaries also leads to more common urban areas, such as parks and playgrounds, being built over.

3. The countryside isn't being concreted overContrary to public perceptions, England is not being covered in concrete. Most people think that more than 50% of England is built upon, but the actual figure is 10.6%. Across the UK as a whole, it's as low as 6.8%. These figures include areas such as parks, gardens, allotments and sports pitches. By the time those have been taken out the figure drops to just 2.27%. The green belt, meanwhile, covers 12% of England.

4. It encourages inequalityThe green belt increases social inequality by acting as a wall that confines urban dwellers at increasingly higher densities. Prof Paul Cheshire of the London School of Economics described it as "a very British form of discriminatory zoning, keeping the urban unwashed out of the home counties – and, of course, helping to turn houses into investment assets instead of places to live".

5. It worsens the housing crisisEngland has a severe housing crisis and the greatest need for homes is in London and the south-east – the area that also has the most green belt land. Greater London contains 35,000 hectares (86,450 acres) of green belt land and there are another 75,000 hectares within the M25. Building on just on just a quarter of that land would provide over a million homes – enough to meet London's needs for generations to come.

6. It's partly why house prices are out of reach for so manyThe green belt constricts supply and forces up land and house prices. Cities that are heavily constrained by the green belt such as Oxford, London and Cambridge have some of the most unaffordable homes in the in the country. This denies decent homes to people on low- and middle-incomes and forces people into long commutes.